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<table width="100%" summary="page for nodal"><tr><td>nodal</td><td align="right">R Documentation</td></tr></table>

<h2>
Nodal Involvement in Prostate Cancer
</h2>

<h3>Description</h3>


<p>The <code>nodal</code> data frame has 53 rows and 7 columns.
</p>
<p>The treatment strategy for a patient diagnosed with cancer of the prostate
depend highly on whether the cancer has spread to the surrounding lymph nodes.
It is common to operate on the patient to get samples from the nodes which can
then be analysed under a microscope but clearly it would be preferable if an
accurate assessment of nodal involvement could be made without surgery.
</p>
<p>For a sample of 53 prostate cancer patients, a number of possible predictor
variables were measured before surgery.  The patients then had surgery to 
determine nodal involvement.  It was required to see if nodal involvement could 
be accurately predicted from the predictor variables and which ones were
most important.
</p>


<h3>Usage</h3>

<pre>
nodal
</pre>


<h3>Format</h3>


<p>This data frame contains the following columns:
</p>

<dl>
<dt><code>m</code></dt><dd>
<p>A column of ones.
</p>
</dd>
<dt><code>r</code></dt><dd>
<p>An indicator of nodal involvement. 
</p>
</dd>
<dt><code>aged</code></dt><dd>
<p>The patients age dichotomized into less than 60 (<code>0</code>) and 60 or over <code>1</code>.
</p>
</dd>
<dt><code>stage</code></dt><dd>
<p>A measurement of the size and position of the tumour observed by palpitation
with the fingers via the rectum.  A value of <code>1</code> indicates a more serious
case of the cancer.
</p>
</dd>
<dt><code>grade</code></dt><dd>
<p>Another indicator of the seriousness of the cancer, this one is determined by
a pathology reading of a biopsy taken by needle before surgery.
A value of <code>1</code> indicates a more serious case of the cancer.
</p>
</dd>
<dt><code>xray</code></dt><dd>
<p>A third measure of the seriousness of the cancer taken from an X-ray reading.
A value of <code>1</code> indicates a more serious case of the cancer.
</p>
</dd>
<dt><code>acid</code></dt><dd>
<p>The level of acid phosphatase in the blood serum.
</p>
</dd></dl>


<h3>Source</h3>


<p>The data were obtained from
</p>
<p>Brown, B.W. (1980) Prediction analysis for binary data. In 
<EM>Biostatistics Casebook</EM>.
R.G. Miller, B. Efron, B.W. Brown and L.E. Moses (editors),
3&ndash;18. John Wiley.
</p>


<h3>References</h3>


<p>Davison, A.C. and Hinkley, D.V. (1997) 
<EM>Bootstrap Methods and Their Application</EM>. Cambridge University Press.
</p>


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